A mouthguard (also known as a mouth protector, mouth piece, gumshield, gumguard or nightguard) is a protective device for the mouth that covers the teeth and gums to prevent and reduce injury to the teeth, arches, lips and/or gums. Mouthguards are most often used to prevent injury in contact sports, as a treatment for bruxism or (temporomandibular joint disorder) TMD, or as part of certain dental procedures, such as tooth bleaching.
Mouthguards may be stock (i.e., ready-made), mouth-adapted (e.g., boil-and-bite), or custom made. Stock mouthguards may be manufactured in pre-formed shapes and in various sizes but have limited adjustment (e.g., trimming with a knife or scissors only) to fit a specific user's mouth. Mouth-adapted mouthguards are typically made of a thermo-plastic material (e.g., ethylene-vinyl acetate) manufactured in a pre-formed shape in various sizes. The mouth-adapted mouthguards are then adapted to fit the user's teeth and gums by heating the mouthguard and molding the mouthguard while it is still warm. More specifically, the mouthguard may be placed in boiling water to heat it and then placed in the user's mouth. The user bites down on the mouthguard to form the mouthguard to the user's mouth (including the user's teeth and gums). Custom-made mouthguards are made by taking an impression of a user's mouth and teeth by a specialist manufacturer to create a mouth protector specifically for that user. The impression may be obtained by specifically designed home impression kit from the guard manufacturer that uses dental putty, or from a dentist who will take an upper impression in dental alginate material, for example